Refrigerating apparatus



Nov. 2, 1937. TOMLINSON 2,097,539

REFRIGERAT ING APPARATUS Filed May 31, 1935 I 2 I INYEXTOR, I

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Patented Nov. 2, 1937 REFRIGERATING APPARATUS Edward J. Tomlinson,Dayton, Ohio, assignor to General Motors Corporation, Dayton, Ohio, acorporation of Delaware Application May 31, 1935, Serial No. 24,260

'7 Claims.

This invention relates to refrigerating apparatus and more particularlyto control means therefor.

Attempts have been made to operate refrigerating apparatus continuouslyso as to eliminate the usual starting and stopping and thereby permitthe use of a smaller apparatus to supply refrigeration. The operation ofa. system in such a manner has disclosed certain difficultiesin'maintaining the proper evaporator and refrigerator temperaturesthereby. In such systems in warm weather the evaporator and refrigeratortemperatures would be too high while in cool weather the temperatureswould be too cool. Also, there was little or no reserve capacity to takecare of ice freezing demands.

It is an object of my invention to provide an improved refrigeratingsystem which is capable of operating continuously and capable ofmaintaining proper evaporator and refrigerator temperatures whenoperating continuously under varying conditions.

It is another object of my invention to regulate the operation of therefrigerating system accord- 25 mg to the refrigerator temperature andto pro vide an additional form of regulation to provide additionalrefrigerationwhen ice freezing is being accomplished.

It is a further object of my invention to pro- 30 vide a refrigeratingsystem in which the evaporating pressure and temperature within theevaporating means is controlled mainly by the box temperature but in'which means are provided for adequately taking care of ice freezingdemands.

Further objects and advantages of the present invention will beapparentfrom the following description, reference being had to theaccompanying drawing wherein a. preferred form of the present inventionis clearly shown.

In the drawing: 7 4

Fig. 1 is ,a view partly in section and partly diagrammatic embodying myinvention; and,

Fig. 2 is a section along the line 22 of Fig. 1,

\ In the embodiment disclosed herein a com pression type ofrefrigerating system is disclosed in which the liquid refrigerant flowsto the evaporating means under the control of a thermostatic valveresponsive .to the temperature of the evaporating means and the flow ofevaporated pressure of the refrigerant within the evaporating The motormeans. driven compressor may be refrigerant out of the evaporating meansis conoperated continuously, if desired, or may be operatedintermittently under low pressure or other form of control. v

Referring now more particularly to the draw-' ing, there is shown acompressor 20 driven by an 5 electric motor 22 for compressing therefrigerant and for forwarding the compressed refrigerant to a condenser24 where the compressed refrigerant is liquefied and collected in areceiver 26. From the receiver 26 the liquid refrigerant is forwardedthrough a supply conduit 28 to a thermostatic valve 30 located withinthe food compartment 32 of a domestic electric refrigerator 34. Theopening and closing of the thermostatic valve 30 is controlled by athermostatic bulb 36 located in heat exchange relation with the upperportion of an evaporating means 38 also located within the foodcompartment 32 and containing a. plurality of ice trays 40 for freezingice cubes.

The liquid refrigerant evaporates within the evaporating means 38 underreduced pressure to cool the air within'the food compartment 32 and forfreezing any water in the ice trays 40. This evaporated refrigerantreturns to the compressor through the return conduits l2 and M which areconnected by an improved control valve 46 which controls the withdrawalof evaporated refrigerant from the evaporating means 38.

This control valve 46 has a cylindrical outer casing 48 provided with avalve housing 50 at one end and a bellows support 52 for closingtheother end. The valve housing 50 has the conduit 42 entering at oneside and opening into a valve chamber 54 which contains a valve 56resting upon a valve seat formed in the upper end of the threadedbushing 58. This valve is connected to the lower end of a square valvestem 60 which is Y threaded into the end plate 62 of a metal bellows 64.This metal bellows B4 is sealed at its upper end to the bellows support52 and contains a 4o compression type coil spring 66 which bears at itsupper end against a threaded adiusting cap 68 and at its lower endagainst the end plate $2 of the bellows M for urging the valve 56 toclosed position. Immediately beneath the end plate 62 5 is a smaller endplate'lll which is sealed to the upper end of a flexible metal bellowsI2 which extends downwardly surrounding the valve stem guide Hand isconnected to and sealed to the valve housing at the lowerportion of the50 valve stem guide 1!.

By this construction, a fluid chamber 16 is formed within the controlvalve which is connectedby tubing 18 to a thermostatic bulb 80 locatedwithin the food or refrigerated compartment 32. This thermostatic bulb80, the tube 18 and chamber 16 are preferably filled with a volatileliquid having suitable characteristics to open and close the valve 56inorder to maintain the -evaporating means 38 at a proper temperature toproperly cool the refrigerator chamber 32. A second chamber is formedwithin the bellows I2 and this is acted upon by the pressure within theevaporating means which communicates with the bellows 12 and its endplate through the return conduit 42,the valve chamber 54 and thepassages surrounding the square valve stem 80. The system may beprovided with a low pressure control switch mechanism 82 which may beconnected to the return conduit 44 and in series with the electric motor22. However, preferably the motor-compressor unit operates continuouslyby closing a manual switch 84 which is connected in parallel with thelow pressure switch 82.

With this system liquid refrigerant is forced into the evaporatorwhenever the evaporator falls below the temperature for which the valve30 is set. This liquid refrigerant evaporates within the evaporatingmeans 38 and creates'a pressure within. When the temperature within thefood compartment 32 is high, the volatile liquid within the thermostatwill expand and increase the pressure upon the end plate 62 of thebellows 64 to move the valve 56 to open position to permit theevaporated refrigerant to be withdrawn from the evaporator by thecompressor 20. When the temperature within the food compartment 32becomes low, the volatile liquid within the thermostat 80 will contract,thus reducing the pressure within the chamber 16 and, permitting thespring I 66 to move the valve 56 to closed position. This will cause therefrigerant pressure within the evaporator to build up and thus to slowdown the evaporation therein. If the valve 56 is closed for a sufficientlength of time the evaporation will finally approach a point where itwill cease altogether. However, the normal position of the valve 56w'il-lbe partially open which will ordinarily maintain at all times theproper evaporator and box temperature within the evaporating means 38and the food compartment 32.

When warm ice trays such as the ice tray 40 are placed into theevaporating means 38, an increase in evaporation takes place within theevaporating means 38 because of the higher temperature imposed on theevaporator. This also creates an increased pressure within the returnconduit 42 and the' valve chamber 54 which will cause an increasedpressure upon the end plate 10 of the bellows." to tend to place a.greater pressure on the valve structure tending to open the valve 56 toa wider open position. This will permit evaporation of the liquidrefrigerant at a more rapid rate so as to cause the freezing of thewater within the ice trays to progress rapidly without reducing theamount of refrigeration provided for the food compartment 32 to -adangerous extent.

Thus, I have provided a refrigerating system which provides for both boxcooling and ice freezing demands and which will permit the continuousoperation of the refrigerant compressor, if desired.

While the form of embodiment of the present invention as hereindisclosed constitutes a pre- 1. Refrigerating apparatus including arefrigerant evaporating means for cooling a medium and a refrigerantcompressing and 'condensing means for supplying liquid refrigerant toand for withdrawing evaporated refrigerant from the evaporating means,and means responsive to the arithmetical sum of the influences of thetemperature of the medium to be cooled and the pressure of therefrigerant within the evaporating means for controlling the withdrawalof refrigerant from the evaporating means.

2. Refrigerating apparatus including a refrigerant evaporating means forcooling 8. medium and a refrigerant compressing and condensing means forsupplying liquid refrigerant to and for withdrawing evaporatedrefrigerant from the evaporating. means, and valve means responsive tothe temperature of the medium to be cooled and to the pressure of therefrigerant within the evaporating means for controlling the withdrawalof refrigerant from the evaporating means.

3. Refrigerating apparatus including a refrigerant evaporating means forcooling a medium and a refrigerant compressing and condensing means forsupplying liquid refrigerant to and for withdrawing evaporatedrefrigerant from the evaporating means, and valve means located at theoutlet of the evaporating means and responsive to the temperature of themedium to be cooled and to the pressure of the refrigerant within theevaporating means for controlling the withdrawal of refrigerant from theevaporating means.

4. Refrigerating apparatus including a cabinet, a refrigerantevaporating means for cooling the interior of the cabinet and providedwith means for freezing ice, a refrigerant compressing and condensingmeans for supplying liquid refrigerant to and for withdrawing evaporatedrefrigerant from 'the evaporating means, and valve means directlyresponsive to the temperature within the cabinet and to the temperatureof the ice freezing means for controlling withdrawal of evaporatedrefrigerant from the evaporating means, said valve means being locatedat the outlet of said evaporating me 5. Refrigerating apparatusincluding a refrigerant-evaporating means for cooling 9. medium and arefrigerant compressing and condensing means for supplyingliquid-refrigerant to and for withdrawing evaporated refrigerant fromthe evaporating means, a control means including valve means forcontrolling the circulation of refrigerant through the evaporatingmeans, temperature responsive means responsive to an increase intemperature of the medium to be cooled to operate the valve means toprovide increased circulation of refrigerant through the evaporatingmeans, and a second temperature responsive means responsive to anincreased temperature of the evaporating means for operating thevalvemeans to provide increased circulation of refrigerant through theevaporating means.

6.'- ,Refrigerating apparatus including a refrigerant evaporating meansfor cooling a medium and a refrigerant compressing and condensing meansfor supplying liquid refrigerant to and for withdrawing evaporatedrefrigerant from the evaporating means, a control means including valvemeans for controlling the circulation of refrigerant through theevaporating means, temperature responsive means responsive to anincrease in temperature of the medium to be cooled to operate the valvemeans to promote circulation of the refrigerant through the evaporatingmeans,

and a second temperature responsive means re- 75 sponsive to anincreased temperature of, the evaporating means for operating the valvemeans to promote circulation of the refrigerant through the evaporatingmeans, one of said first and second temperature responsive means beingeffective to operate the control means to stop the reirigerantcompressing means upon a fall in temperature. v v

7. Refrigerating apparatus including a refrig- 10 erant evaporatingmeans for cooling a medium and a refrigerant compressing and condensingmeans for supplying liquid refrigerant to andfor withdrawing evaporatedrefrigerant from the evaporating means, and means responsive .to thearithmetical sum of the influences of the temperature of the medium andthe temperature of the evaporating means for. controlling circulation ofrefrigerant through the evaporating means.

EDWARD J. 'rommsou. 10

